Systemic lupus erythematosus (SLE) Flashcards
What type of disease is SLE?
It is a rare autoimmune disease
SLE is a part of a family of diseases- what are the other diseases in that family?
- Rheumatoid arthritis
- Sjogren’s syndrome
- Dermatomyotis
- Polymyositis
- Systemic sclerosis
- SLE
What is the gender ratio for SLE?
• Gender ratio M:F=1:9
At what age to SLE’s present?
15-40 years
Which ethnicities is SLE more prominent?
Afro-Carribean, Asian, Chinese
What is the prevalence of SLE?
4-280/100,000
What are the gene associations with SLE?
Genetic associations: with multiple genes implicated Fc receptors, IRF5, CTLA4, MHC class 2 HLA genes and complement deficiency- c1q and c3.
how does SLE present?
Malaise, fatigue, fever and weight loss. Accompanied by lymphadenopathy (abnormal size and shapes of lymph nodes).
What are the specific features of SLE?
- Butterfly rash
- Alopecia
- Arthralgia- joint pain
- Raynaud’s phenomenon
What are the additional pathological features of SLE?
- Inflammation of the kidney, CNS, heart and lungs
- Accelerated atherosclerosis
- Vasculitis
What are some of the roles of B cells in the immune response
- Antigen presentation
- Antibody production
- Activate antigen-presenting cell function
- Regulate T cell activation anergy or differentiation
- Produce cytokines
- Regulate FDC differentiation
How is B cell function different in SLE?
In SLE genetic factors increase B cell reactivity so that it can directly result in autoantibody production and end-organ damage.
It can also increase the capacity of B cells to enhance the function of a variety of other cells.
What are the steps for the formation of autoantibodies
1) abnormal clearance of apoptotic cell material
2) dendritic cell uptake of autoantigens and activation of B cells
3) B cell Ig class switching and affinity mutation
4) IgG autoantibodies
5) Immune complexes
6) complement activation cytokine generation
What is the significance of the overactive B cells?
Overactive B cells are exposed to the autoantigens and the plasma cells begin to produce auto antibodies which form immune complexes. This deposits in tissues (mainly kidneys and skin) which then activates complement in the tissues.
How is SLE diagnosed?
1) Send serum to check for anti-nuclear antibodies (not diagnostic of SLE specifically)
2) Serum is then combined will cells and if ANA (antinuclear antibodies) are present, they will bind to the cell’s nuclear antigens. A fluorescently labelled antibody is added that binds to ANAs and you observe the pattern of attachment.
What are the 3 things you can test the serum with?
ANAs
Anti-dsDNA and Sm
Anti-Ro and /or La
Name some other tests done to identify SLE?
- Increased complement consumption- patients with active lupus will have more complement bound to immune complexes and so the blood complement will be low in active lupus
- Anti-cardiolipin antibodies
- Lupus anticoagulant
- B1 glycoprotein
What are the haematological tests done to diagnose SLE?
- Lymphopenia, normochromic anaemia- SLE patients will present with autoimmune haemolytic anaemia- antibodies will bind to RBC surfaces and they are extravascularly removed in the spleen.
- Leukopenia, AIHA, thrombocytopaenia
What are the renal tests you can do to diagnose SLE?
- Proteinuria, haematuria
* Active urinary sediment
How do you assess the severity of SLE?
1) Identify pattern of organ involvement
2) Monitor function of affected organs-
• Renal- BP, U&E, urine sediment GFR
• Lungs/CVS- lung function tests, echocardiography
3) Identify the patterns of autoantibodies expressed
• Anti-dsDNA, anti-Sm- renal disease
• Anti-cardiolipin antibodies
What are the clinical features of SLE
- Wt loss, fatigue, malaise, hair loss
- Alopecia
- Rash
What are the lab features of SLE?
- ESR
- Increased complement consumption
- Increased anti-dsDNA
- Other Abs e.g ANA and CRP poor indicators
How are people with SLE split up into different categories?
People who have the disease are split into 3 groups:
1. MILD- joint pain some skin involvement- there is no sign of organ involvement
2. MODERATE- inflammation of other organs, pleurits, pericarditis, mild nephritis
3. SEVERE- severe inflammation in vital organs
• Severe nephritis
• CNS disease
• Pulmonary disease
• Cardiac involvement
• AIHA, thrombocytopaenia, TTP
What is the treatment of mild SLE?
Paracetamol +/- NSAIDs and renal function is monitored
Hydroxychloroquine- for arthropathy, cutaneous manifestations, mild disease activity
Topical corticosteroids
